Open AccessOrthogonal long-period fiber grating for directly exciting the orbital angular momentum
Author(s) -
Zhao Liu,
Guoxuan Zhu,
Yali Li,
Jie Yu,
Zhiyong Bai,
Jun He,
Yiping Wang
Publication year - 2020
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.399929
Subject(s) - optics , orthogonal polarization spectral imaging , angular momentum , grating , polarization (electrochemistry) , physics , laser , materials science , chemistry , quantum mechanics
An orthogonal long-period fiber grating (OLPFG) is proposed and demonstrated for directly exciting the orbital angular momentum (OAM), without the need for other devices. This grating was produced using CO 2 laser exposure in the orthogonal direction. A helical phase was then optically induced in the OLPFG, with a chirality determined by the structure of the OLPFG. In this study, ±1-order OAM resonances were respectively observed in OLPFGs with a different orthogonal direction. The conversion efficiency of OAM mode in this process was 99%, and the purity was higher than 98%. In addition, incident light in any polarization state was observed to excite OAM with the same polarization.